1. Field of the Invention
The present invention relates to a penpoint or nib used on fountain pens and other writing materials and more particularly to a penpoint, which can write on paper in any direction and, after the penpoint is rotated about a pen axis, can also write at any rotated position and at any angle with respect to the paper, and which has a writing brush function whereby it offers a soft touch when placed in contact with paper and, according to the writing pressure, changes the width of strokes to produce thick or fine lines thus realizing a variety of modes of handwriting.
2. Prior Art
To eliminate a disadvantage of conventional fountain pens and other writing instruments with a single penpoint that they can only write in a certain direction, a polygonal penpoint assembly has come to be used in recent years, which consists of three penpoint pieces combined together, each having a similar shape to the conventional single penpoint. This polygonal penpoint assembly has three penpoint pieces combined back to back. It has three blades formed convex in three circumferential directions around the center axis of the pen and V-shaped recessed surfaces between the blades, with a hemispheric writing tip formed at each front end of the blades. Because of the hemispheric writing tip, the polygonal penpoint assembly can write on paper in any direction and, after the penpoint is rotated about a pen axis, can also write at any rotated position and at any angle with respect to the paper.
Some polygonal penpoint assemblies are made of molded resin and have their writing tip ground, rounded or cut to suit their needs. There are so-called plastic pens that use a bar-like core extrusion-molded of polyacetal resin and having continuous guide holes. So-called plastic fountain pens have a plate-like pen body with a porous guide hole formed at the center thereof. So-called marker pens have polyester fibers bound together with resin and formed into a bar-like core while maintaining porosity. These pens utilize flexibility and self-lubrication ability of the resin materials and have simple constructions and therefore high productivity.
To enable the pen to write on paper in any direction and, after the penpoint is rotated about a pen axis, to also write at any rotated position and at any angle with respect to the paper, however, the conventional polygonal penpoint assembly structure has a drawback that when a writing pressure is applied to the penpoint, the tips of the penpoint pieces do not move or shift relative to each other, with the hemisphere portions at the tips remaining almost unchanged, so that it feels like a hard pen such as a ball-pointed pen.
As for the conventional resin-molded penpoints, there are the following problems. Because of the softness of the resin materials, the resin-molded penpoints cannot withstand a long period of use and easily deform under the writing pressure, resulting in significant wear. Further, although the resin materials have resiliency, the degree of resilience is not enough to cause such large deflections to the penpoint as will deform the writing tips and change the width of strokes. Thus, the characters can only be written with strokes of a fixed width.